Roll Skia from a4ad5b369313 to 20e9cc928715 (3 revisions) (flutter/engine#42926)

https://skia.googlesource.com/skia.git/+log/a4ad5b369313..20e9cc928715

2023-06-16 jvanverth@google.com [graphite] Set Vulkan viewport and scissor
2023-06-16 johnstiles@google.com Reject first-class arrays on initializers in strict-ES2 mode.
2023-06-16 johnstiles@google.com Use IRHelpers class to assemble matrix-multiply workaround.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC brianosman@google.com,chinmaygarde@google.com,herb@google.com,rmistry@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Skia: https://bugs.chromium.org/p/skia/issues/entry
To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

DEPS

@@ -18,7 +18,7 @@ vars = {
   'llvm_git': 'https://llvm.googlesource.com',
   # OCMock is for testing only so there is no google clone
   'ocmock_git': 'https://github.com/erikdoe/ocmock.git',
-  'skia_revision': 'a4ad5b369313dec3eee947fbccbf85dd938a8b0e',
+  'skia_revision': '20e9cc92871530709ad40ea93f1fd4a7e0b1779a',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.

engine/src/flutter/ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: 4a4d69136b0eea40e3b023b6c19663d4
+Signature: 1106eb8ac91bd3b419a448c45d25d159
 
 ====================================================================================================
 LIBRARY: etc1